Answer:
11
Explanation:
n(A) means the number of elements in set A
Element 1=-10
Element 2=-9
Element 3=-8
Follow the pattern
Element 4=-7
Element 5=-6
Element 6=-5
Element 7=-4
Element 8=-3
Element 9=-2
Element 10=-1
Element 11=0
There are 11 elements in set A.
Also this has the same number of elements as {0,1,2,...,8,9,10} which has (10+1) elements.